Patent GB-851726-A (GB)
Title: Electronic receiver for a teleprinter
Inventor: SUSICKY STANISLAV
IPC: H04L17/30
Filed: 1957-05-14
Abstract: 851,726. Printing telegraph receivers. TESLA NARODNI PODNIK. May 14,1957, No. 15285/57. Class 40(3). In an electronic receiving arrangement for a teleprinter comprising an input circuit coupled to the line by a transformer, and linked to a memory circuit constituted by a number of serially connected bistable two-condition members, a time base and a selecting-translating circuit connected to the output of the memory circuit, the input circuit which applies the received telegraphic impulses to the seriesconnected memory circuit is connected to a circuit capable of reversing the final memory-circuit member which is coupled to the time-base to control its operation and which is also connected to a reversing circuit associated with all the remaining members of the memory circuit and operative to control the restoration of all said remaining members of the memory circuit to a normal condition, and a valve in the translating circuit is connected to a device which delays the operation of a relay controlling the translating relays and is controlled by a non-stable trigger circuit which determines the duration of the pulses supplied to the windings of the printing magnets of the receiver. During the stop element (or rest) period of the receiver the states of the trigger circuits E2 - E6 correspond to the five-units of the received signal, and the trigger circuit E7 representing the start element has its upper and lower sections non- conducting and conducting respectively. The start element applied over the line Ll and transformer TR1 makes the lower section of El conductive and a negative pulse from its anode circuit reverses the valve circuit E7 so that its lower section becomes non-conductive and passes a positive pulse differentiated by capacitor C10 and resistor R83 to make the valve E8 momentarily conductive to pass a negative pulse to the lower grids of the circuits E2 - E6 so that they are all in the condition of the top section conducting. A positive pulse is also passed from the anode of the lower section of the circuit E7 via resistor R85 to the grid of an oscillator circuit comprising valve E10, (Fig. 3), in conjunction with a frequency determining circuit C11,C12, R89, R90, R91 to produce a rectangular wave form at 50 c.p. s. which is differentiated by capacitor C9 and resistor R82 to produce pulses which at 10, 30, 50 m.secs render the valve E9 conductive to pass negative pulses at those instants to the grids of the lower sections of the valve circuits E2 - E6. The start element makes the top and bottom sections of the valve circuit El non-conductive and conductive respectively, and at 10 m.secs. the pulse from the valve E9 allows the valve circuit E2 to take over the condition of El, i.e. top and bottom sections non-conducting and conducting respectively. The first code element conditions circuit El, and if it is a mark (positive) makes the upper part conductive and the lower part non- conductive. At the time 30 m.secs., the pulse condition on E2 is transferred, after with a slight delay introduced by resistors R19, R22 and capacitor Cl, to E3, and the first code signal element is passed from circuit El to the circuit E2. At the time, shortly after 110 m.secs., the start element is applied to the circuit E7 and the five code elements are registered on the circuits E2 - E6, the first element being on E6 and the fifth element on E2. Also the registration of the start element on the circuit E7 changes the lower section to a conducting condition with the consequent application of a lowered voltage to the grid of the valve E10 which becomes non-conductive and suppresses the operation of the oscillator. Operation of the printing telegraph receiver. During the registration of the code elements and until the start element has reached the circuit of valve E7, this valve has its upper and lower sections conducting and non-conducting respectively. When the start element is registered on the valve E7, its condition is reversed and the lower section conducts so that a strong negative voltage pulse is applied to the normally conducting righthand section of the valve E1 6 which controls the non-stable trigger circuit and which applies a positive pulse to the right-hand side of a valve E15 having a relay K whose operation is slightly delayed by the left-hand section of the valve E15. The negative pulse from the valve E7 is also applied over conductor 0 to the right-hand grid of the valve E14. The left-hand side of the valve E16 becomes conducting and passes a negative pulse to the normally conducting right-hand side of the valve E14 which cuts off and applies a positive pulse to both grids of the valves E12, E1 3 and to the left-hand grid of the valve E14. The outputs of the lower sections of the circuits E6 - E2 are applied over conductors 1 - 5 to the grids of the valves E12, E13 and to the left-hand grid of the valve E14. The circuits E2 - E6 on which mark (positive) elements have been registered have positive voltages on the associated conductors 1 - 5, and the corresponding valve sections conduct so that relays (A,F), (D,I), (H,C), (B,G) and E are selectively operated. The operated relay or relay groups lock up over contacts e, a, i, c, b and operated contact kl of the relay K. By the operation of contact k2, an operating circuit is completed to a printing magnet A<SP>1</SP>, Bt, - Y<SP>1</SP>, Z<SP>1</SP> or to a function control device over the contacts of the selectively operated magnets A,B - I. For upper-case characters, a relay P is operated in series with the magnet FS by the figure-shift combination and locks in the operated condition at contact p1 until the letter-shift combination has been received, the current through magnet LS passing also through the winding II of relay P in such manner as to effect release of the relay. With the relay Poperated, the bell BL is operated via contact p4 instead of the magnet for J<SP>1</SP>, and via contact p3, the magnet WRU controlling the answer back is energized in lieu of the printing magnet D<SP>1</SP>. Specification 826,148 is referred to.